1. Field of the Invention
The present invention relates to a solar battery module and, more specifically, to a solar battery module used for solar power generation.
2. Description of the Background Art
Recently, use of clean energy has attracting much attention, and use of solar batteries has been promoted. Further, along with mass production of solar batteries, manufacturing cost has been reduced. Conventionally, the solar battery has been dominantly used in the form of a solar electricity generation plant where a large number of solar batteries are arranged, or used for securing power supply at a remote location. Recently, it becomes more and more popular to install a solar battery module panel on a house roof or on an outer wall of a building in town, generate power thereby and use the power in the similar manner as the electricity supplied by the conventional electric power company.
Such a solar battery module panel has a plurality of photovoltaic elements resin-sealed between a surface cover glass and a back cover film. Conventionally, a transparent glass having mirror surface has been used as the surface cover glass, causing public nuisance caused by light. In order to solve this problem, use of a figured glass having a particular shape on its surface formed by pressing the glass has been proposed. Japanese Patent Laying-Open No. 11-74552 discloses a method for forming unevenness or roughness on the light entering surface of a glass substrate.
As a structure enabling significant cost reduction of the solar battery module, a solar battery module formed on a substrate has been proposed, which is obtained by successively forming a transparent electrode layer, a semiconductor layer and a back electrode layer from the light entering side in this order, on a transparent insulating substrate having the same size as the surface cover glass. This structure is characterized in that sealing resin to be filled between interconnections of photovoltaic elements and between the elements and the cover glass is unnecessary, and that energy loss caused by light absorption by the surface cover glass and degradation in property caused by yellowing of resin are not experienced.
FIG. 11 is a cross section representing a schematic structure of an example of the conventional solar battery module.
Referring to FIG. 11, the solar battery module includes a transparent insulating substrate, a transparent electrode layer 2 formed on a surface different from a light entering surface of transparent substrate, a photo semiconductor layer 3 formed on transparent electrode layer 2, and a back electrode layer 4 formed on photo semiconductor layer 3. A photo semiconductor element 5 formed by successive stacking of transparent electrode layer 2, photo semiconductor layer 3 and back electrode layer 4 is divided into a plurality of areas, and the areas are electrically connected in series or in parallel with each other.
The solar battery module is sealed and protected by a filler resin 6 and a back cover film 7, so as to protect photo semiconductor element 5. Further, the solar batteriesealed in this manner has a frame 8 attached thereto.
The process steps for manufacturing the conventional solar battery module structured as described above includes the steps of film formation such as plasma CVD and sputtering, as well as the step of laser processing. In order to stably perform these process steps, the conventional solar battery module has the light entering surface of transparent insulating film 1 made flat.
It has been pointed out, however, that when the conventional solar battery module structured as described above is arranged on a roof or an outer wall of a building, sunlight may possibly be reflected and enter neighboring household dependent on the angle between the sun and the solar battery module, resulting in public nuisance.
In order to solve this problem, use of a figured glass, which scatters light, as the substrate surface has been proposed as described above. When such a glass is to be used, detailed study of the texture specification of the figured glass or special laser processing condition becomes necessary, resulting in increased cost. When unevenness is to be formed on the glass substrate itself as disclosed in Japanese Patent Laying-Open No. 11-74552, glass processing involves high temperature or use of a highly reactive solution such as hydrofluoric acid, and therefore the unevenness cannot be formed after completion of the module. When the glass substrate itself is processed in advance before fabrication of the module, it becomes impossible to laser-cut the semiconductor layer or the electrode layer from the side of the glass substrate. Though blasting is possible as a method of forming unevenness on the glass substrate, blasting deteriorates glass strength.
In the conventional manufacturing of a solar battery module, glass substrates of different lots have different tones. Therefore, the completed solar battery module also has difference in tone.
An object of the present invention is to provide a solar battery module solving the above described problems, effectively preventing public nuisance caused by light reflection on the light entering side and having uniform tone.
In accordance with an aspect of the present invention, a solar battery module is provided. The solar battery module includes a transparent insulating substrate having first and second surfaces, a first electrode layer formed on the first surface of the transparent insulating substrate, a photosemiconductor layer formed on the first electrode layer, a second electrode layer formed on the photosemiconductor layer, and an anti-glare film formed on the second surface, to which light enters, of the transparent insulating substrate.
The anti-glare film includes an organic material binder and organic particles, an organic material binder and inorganic material particles, an inorganic material binder and organic material particles, or an inorganic material binder and inorganic material particles.
Preferably, the organic material binder contains an acrylic resin, a fluororesin, or a mixed resin thereof. For example, the acrylic resin of said organic binder includes an acryl copolymer containing a hydrolyzable silyl, containing a group represented by the following molecule structure: 
(in the formula, R1 represents an alkyl having 1 to 10 carbon atoms, R2 represents a monovalent hydrocarbon group selected from the group consisting of alkyl, aryl and aralkyl having 1 to 10 carbon atoms or a hydrogen atom, and a represents 0, 1 to 2), and said fluororesin is a fluororesin containing a hydroxyl group.
Preferably, the organic material particles consist of an acrylic resin, a fluororesin, a polyethylene wax or a mixture of at least two of these.
Preferably, the inorganic particles consists of silica.
Preferably, the inorganic material binder is formed of silica or alkyl silicate.
Alkyl silicate may contain of ethyl silicate, butyl silicate, a mixture thereof.
Further, the inorganic material binder may be complexed with an organic material.
Preferably, a catalyst may be added to the binder.
Further, the catalyst may contain an organic tin compound.
Preferably, the diameter of the particles is 1 to 10 xcexcm, and the mixing ratio between the binder and the particles is such that the weight of the particles is 1 to 10 when the weight of the binder is 100.
Further, preferably, a film formed of a surfactant is provided interposed between the transparent insulating substrate and the anti-glare film.
The anti-glare film may preferably has a rough surface.
A surface protection film formed on the anti-glare film may further be provided.
According to another aspect of the present invention, a solar battery module is provided. The solar battery module includes a transparent electrode, a semiconductor photoelectric conversion layer and a back electrode layer formed in order on a first main surface of a transparent insulating substrate having first and second main surfaces, and an anti-glare film formed on the second main surface of the transparent insulating substrate, the anti-glare film contains an organic polymer, an inorganic polymer or a composite material thereof, and has a surface having fine roughness suitable for scattering light.
Preferably, an acrylic resin, a fluororesin or a mixed material of these may be used as the organic polymer contained in the anti-glare film.
For example, the acrylic resin contained in the anti-glare film includes an acryl copolymer containing a hydrolyzable silyl, containing a group represented by the following molecule structure: 
(in the formula, R1 represents an alkyl having 1 to 10 carbon atoms, R2 represents a monovalent hydrocarbon group selected from the group consisting of alkyl, aryl and aralkyl having 1 to 10 carbon atoms or a hydrogen atom, and a represents 0, 1 to 2), and said fluororesin is a fluororesin containing a hydroxyl group.
Preferably, a catalyst may be added to the anti-glare film.
Further, preferably, the catalyst contains an organic tin compound.
Preferably, alkyl silicate may be used as a raw material of the inorganic polymer contained in the anti-glare film.
Preferably, ethyl silicate, butyl silicate or a mixed material of these may be contained as the alkyl silicate.
Preferably, the anti-glare film contains silica obtained from an inorganic polymer.
More preferably, a surfactant may be interposed between the second main surface of the transparent insulating substrate and the anti-glare film.
More preferably, a dirt preventing film formed on the rough surface of the anti-glare film is further provided, the dirt preventing film having a flat surface.
According to a still further aspect of the present invention, a solar battery module is provided. The solar battery module includes a transparent electrode layer, a semiconductor photoelectric conversion layer and a back electrode layer formed in order on a first main surface of a transparent insulating substrate having first and second main surfaces, the second main surface of the transparent insulating substrate is covered by an anti-glare film having a rough surface texture having fine roughness suitable for scattering light, or the second main surface itself is processed to have a rough surface texture, the rough surface texture being covered by a surface film approximately maintaining the roughness, and the surface film includes an organic polymer, an inorganic polymer or a composite material thereof.
Preferably, the organic polymer included in the surface film may be an acrylic resin, a fluororesin or a mixed material thereof.
For example, the acrylic resin of the surface film includes an acryl copolymer containing a hydrolyzable silyl, containing a group represented by the following molecule structure: 
(in the formula, R1 represents an alkyl having 1 to 10 carbon atoms, R2 represents a monovalent hydrocarbon group selected from the group consisting of alkyl, aryl and aralkyl having 1 to 10 carbon atoms or a hydrogen atom, and a represents 0, 1 to 2), and the fluororesin is a fluororesin containing a hydroxyl group.
Preferably, alkyl silicate may be used as a raw material of the inorganic polymer contained in the surface film.
Preferably, ethyl silicate, butyl silicate or a mixed material thereof may be included as the alkyl silicate.
Preferably, the inorganic polymer contained in the surface film includes silica.
According to a still further aspect of the present invention, a solar battery module is provided. The solar battery module includes a transparent substrate, a semiconductor photoelectric conversion layer, a filler resin and back cover, a light entering surface of the transparent substrate is covered by an anti-glare film scattering light, or the light entering surface itself is processed to have a rough surface texture, and 60xc2x0 glare of the light receiving surface of the solar battery module having the rough surface texture or the anti-glare film is at most 60.
Preferably, 60xc2x0 gloss of the light receiving surface of the solar battery module having the rough surface texture or the anti-glare film is at most 45.
More preferably, 20xc2x0 gloss of the light receiving surface of the solar battery module having the rough surface texture or the anti-glare film is at most 20 and, more preferably, at most 10.
According to a still further aspect of the present invention, a method of manufacturing a solar battery module is provided.
The method of manufacturing a solar battery module includes the steps of forming a first electrode layer on a first surface of a transparent insulating substrate having first and second surfaces, forming a photosemiconductor layer on the thus formed first electrode layer, forming a second electrode layer on the thus formed photosemiconductor layer, and forming an anti-glare film containing a binder and particles on the second surface, to which light enters, of the transparent insulating substrate, and the anti-glare film is formed after the first electrode layer, the photosemiconductor layer and the second electrode layer are formed on the first surface of the transparent insulating substrate.
The anti-glare film includes an organic material binder and organic material particles, an organic material binder and inorganic material particles, an inorganic material binder and organic particles, or an inorganic material binder and inorganic material particles.
Preferably, a catalyst may be added to the binder.
More preferably, the catalyst contains an organic tin compound.
According to a still further aspect of the present invention, a solar battery module is provided.
The solar battery module includes a transparent insulating substrate having first and second surfaces, a first electrode layer formed on the first surface of the transparent insulating substrate, a photosemiconductor layer formed on the first electrode layer, a second electrode layer formed on the photosemiconductor layer, and an anti-glare film formed on the second surface, to which light enters, of the transparent insulating substrate, and arithmetic mean roughness Ra of the anti-glare film is within the range of 0.1 to 10 xcexcm.
The anti-glare film contain an organic material binder and organic material particles, an organic material binder and inorganic material particles, an inorganic material binder and organic material particles, or an inorganic material binder and inorganic material particles.
Preferably, a catalyst may be added to the anti-glare film.
Preferably, the catalyst may contain an organic tin compound.
As the solar battery module in accordance with the present invention includes an anti-glare film provided on the light entering surface of the transparent insulating substrate, the problem of public nuisance caused by light reflection can effectively be prevented.
By the method of manufacturing a solar battery module, the anti-glare film is formed after the element portion is formed on the surface of the transparent insulating substrate. Therefore, without the necessity of using an expensive figured glass or the like as the substrate, the appearance of the solar battery module can be improved to prevent reflection or public nuisance caused by light. Further, as the anti-glare film is formed last, the basic steps of manufacturing the solar battery module are kept unchanged, while the appearance can be improved.
When a binder resin and the particles of the anti-glare film are both organic materials, for example, good adhesion is attained, so that dropping of particles or separation of the film itself can be suppressed, and hence superior solar battery module is obtained.
When the anti-glare film includes organic material binder and organic material particles, the amount of incident light is not so reduced as to affect practical use, and sunshine can be utilized effectively. Further, the inorganic particles do not much suffer from the problem of deterioration, and hence a solar battery module having superior weather resistance can be obtained.
When the anti-glare film incorporates an inorganic material binder and organic material particles, the amount of incident light is not reduced and the sunshine can be utilized effectively. In addition, the organic material particles relax strain in the binder layer, suppressing generation of cracks, and therefore a solar battery module having superior weather resistance is obtained.
When the anti-glare film incorporates an inorganic material binder and inorganic material particles, the amount of incident light is not so reduced as to affect practical use, so that sunshine can be effectively utilized, and as both materials are inorganic, good adhesion is attained. Further, as the inorganic material binder and the inorganic material particles do not much suffer from the problem of deterioration, a solar battery module having superior weather resistance can be obtained.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.